Meltblown fibers can be manufactured with very fine diameters, in the range of 1-10 microns, which is very advantageous in forming various kinds of non-woven fabrics. However, meltblown fibers are relatively weak in strength. To the contrary, spunbond fibers can be manufactured to be very strong but have a much larger diameter, in the range of 15-50 microns. Fabrics formed from spunbond are less opaque and tend to exhibit a rough surface since the fiber diameters are quite large. In addition, spinning of thermoplastic resins through a multi-row spinnerette, according to the spinning technology taught in U.S. Pat. No. 5,476,616, is quite challenging because of the fast solidification of the outer rows and/or columns of filaments. Due to this fast solidification in the outer rows and/or columns, the filaments tend to be larger and/or form rope defects with adjacent inner rows and/or columns of filaments.
The problem, up to now, is that no one has been able to find a way to extrude small fibers, having a diameter matching those of meltblown fibers, yet having the strength of spunbond fibers.
Now, a process for forming a non-woven web has been invented which solves this problem.